Heating system



Jam, 25, 1949. w T r I 2,460,207

HEATING SYSTEM Filed May 15, 1944 2 Sheets-Sheet 1 ATTORNEY Patented Jan. 25, 1949 HEATING SYSTEM Emil 0. Wirth and Frederik Barfod, South Bend, Ind, assignors to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application May 15, 1944, Serial No. 535,591

4 Claims. (01. 236-9) This invention relates to heating systems and particularly to automatic heating systems using liquid fuel.

It is an object of the present invention to provide an efi'icient and efiective heating system adapted to maintain room temperatures substantially uniform.

It is another object of the invention to provide a device of this character wherein gasoline or another liquid fuel may be used and supplied under pressure and metered while being maintained under pressure.

Further objects of the invention are: to provide a device of this character wherein the danger of fire is reduced to a minimum; to provide a device of this character wherein a mixture of fuel and air is delivered to the burner of the heater and is capable of being readily ignited and burned; to provide a device of this character adapted to maintain the fuel and air difierential pressures in a substantially constant proportion so that a substantially constant fuel to air ratio is obtained; to provide a device of this character that may be arranged in a compact unit; to provide a device of this character wherein the fuel may be at least partially warmed before being mixed with air in the proportioning device, an arrangement particularly valuable in starting the heater when cold; to provide a device of this character for controlling the fuel warming means; to provide a device of this character wherein the throttle may be controlled by thermostatic means; and to provide means for controlling the motor. of the system which circulates air therethrough, said means including a room thermostat and a thermostat adjacent the heater together with means for by-passing one of the thermostats.

Still further objects of the invention are to provide a device of this character which may be built at reasonable cost and which is relatively simple in construction, operation and maintenance.

Other objects and advantages of the invention' will be readily apparent to those skilled in the art from the following description taken in connection with the accompanying drawings which represent a preferred embodiment of the invention. After considering this embodiment skilled persons will understand that many changes may be made without departing from the principles disclosed; and the use of any structures; arrangements, or modes of operation that are properly within the scope of the appended claims is contemplated.

In the drawings:

Figure 1 is a diagrammatic or schematic View of a building embodying the present invention; and

Figure 2 is an enlarged diagrammatic view ,of the heater and fuel supply control means.

Throughout the drawings similar reference characters represent similar parts although where such parts are modified in structure and operation, they are given a further differing reference character.

Referring first to Figure 1, there is shown a building having a lower room H), which may be in the basement, and an upper room 12. The heating device is indicated generally at I4 and comprises a casing I 6 having hot air discharge ducts I8, there being shown a plurality of such ducts which may lead to various rooms to convey heated air thereto. One of the ducts I8 is shown extending upwardly to a hot airregister 29 adapted to discharge heated air into the room l2. Cold air is adapted to be taken from the room l2 through a register 22 in the floor thereof and conducted by a duct 24 to a horizontal duct 25 which is connected with the casing I6. An electric motor 28 is provided for operating a fan 39 in the duct 26 to effect circulation of air through the casing and ducts. The electrical system for the motor comprises a source of.

power which, as shown, is a battery 32, although any other sultable source of electric power may be used. The battery is grounded at 36 and a wire 35, leads to a thermostat 38 from which a wire til leads to a thermostat 42. From the latter thermostat a wire 44 leads to the motor which is grounded at 46. With this arrangement the thermostats are in series. A by-pass 48 is provided about the thermostat 42 and is controlled by a switch 50. The casing it is mounted on supports 52 and is provided with a heating unit indicated generally at 54 which is disposed within the casing.

Referring to Figure 2 the heater unit includes a tube axially disposed in the casing l6 and which discharges into a chimney 62, Figure 1.

The tube 60 defines a combustion chamber 64 within which is axially arranged a heating tube or burner 65 spaced from the inner wall of the tube to by lugs 68 which are spaced longitudinally and circumferentially relative to the tube 60 and are adapted to permit flow Of air through said tube. The tube 66 is preferably loosely packed with fine metal shavings 69 of suitable character, such, for example, as steel wool, and is provided with a plurality of discharge orifices The carbureting device comprises a body 80- which is supported within the casing I6 by means of arms 82, said body 80 being provided with a flange 84 adjacent the innerend, as-viewed in the drawings, which support radialvanes 8'6- which extend longitudinally within the"casingIE for radiating heat from the burner and'heating the air passing through the casing. The body 8!) includes an induction passage 88 having an an" inlet 99 receiving air from the duct 26, and an air outlet in which the adjacent end ofthe tub'e 69 is received tightly enough to prevent leakage betweensaidtubeand' the body 85. If desired; a suitable gasket or the like may be provided he tween said'tube fill-arid body'fiil. The'air' inlet 99 is controlled by athrottle valve 92 mounted on a throttle shaft 941 having a lever Q6 fixed thereto which may be manually actuated or ad justed; or if desired, maybeconnectedwith atemperature-responsivedevice" or thermostat 98 by means of a rod I99. The thermostat um'ay, if desired be positioned adjacent the heater, or it may be located'imtheroomtobe heatedsuch-asroom I2: If -located 'in room I2 the thermostat may be positioned-many convenient part of the room, although as shown in the drawing, it is locatedad-jacent the floor of said room I2; t isalso preferablethatthe opening through the duct- 25' through which the rod 86 passes be snug enough to prevent appreciable leakage of air through said opening. A Venturiz M2 is positioned in theinduction passage posterior to the throttle valve 92, this arrangement: being found to improve the mixing of: fuel-and air; The Venturi comprises separable inlet and outlet sections and is formed on anannularchamber I94 which communicateswviththe interior of the 'v'enturi through -an -annu1ar: slot I06 so as -to 'be subjectedto Venturi depression;

Afuel nozzleis provided inthe induction passageposterior tothe Venturi and-maybe of any suitable type sueh,=-for example-anyof" the no zles shown in 11116: Barfod and Wirth= Patent 2,445,846,grantedJuly-Zl, 194$ The type shown in here is that illustrated in Figures 1- and'2 of said application andinasmuch as saidnozzle'is fully' described thereinit will bedesoribed'but briefly herein as including a'member IEIB mounted in the wall of the-body 8i and which extends transversely of the-induction passage 83- and'is provided with areduced diameter end portion which projects intoan enlarged portion of a member III} receivingfuehfrorn: a fuelconduit iiZ. Air from the casing. I Gisbledint'othe fuel nozzle through a bore I M inmember H38 and mixes with theiuel in said nozzle to form an emulsion which is dischargedinto theinduct-ion passage from annular groove H5. If desired, the free end of'membert I'BB may be turned at I It in a direction to receivethe impact of air fiowing through the casing; An alternativearrangemerit is toconriectthe bore.- H4 with an impact tub'e I25 whichalsoserves another purpose to be described hereinaften-saidf impact tube I28 bemg disposed in th'e'ihductionT passage between the throttle'valve' and-versus.

rivedfrom the throatof the Venturi' I02.

Fuel flow control The flow of fuel to the heater is regulated or controlled by an unmetered fuel pressure control or regulator unit indicated generally at I30, which registers or determines the fuel pressure on the upstream side of a fuel metering orifice I32, and a discharge control unit;-indicatedgenerally at I3'4-.which"registers or determines theprcssure of fuel on the downstream side of said meteringrorifice I32. The units 339 and I34 are of a character similar to those disclosed in the above noted Barfod and Wirth application with such modificationsthereof as are necessary to adapt same fez-use in connection with the present heating system.

As shown, the regulator unit I38 is positioned outside the casing IB'and may be located either adjacent-to the heater or, preferably, at a point remote enough therefrom to prevent overheating, thereby minimizing the danger of fire from this cause. Th'e'unit istf-is dividedintc'th'ree'chambers to the diaphragms to prevent" cutting of same and between whiclr'said diaphragin's are clamped by centrally disposed cylindrically'recesscd rivets I54 and i565 Theendsof a pin orrod I58"are received in the recessof the rivets" andsaid ends are preferably rounded to provideangularly a'djust'a'bl'e one-wayconnections between the diaphragms whereby slight misalignmentsmay be accommodatedwitl'iout' binding.

The chamber I'38"of'- the regulator" unit- I30 is connected to'the Venturi' annulus I04 by'means ofa conduit orpass'age- IBB and a-conduit I JZ'and is therefore subjected to a' -pressure primarily de-' A re striction I64"may be provided in the passage I69- if' desired, which alternately ma be located in passage: EBZbetweenthe junction ofpassages I60 and Iii'Ta'ndth'e Venturi annulus: Chamber I40 is connect'ed tothe Vnthrientraiice by conduit lto' which maybe-prcvidedwith a restriction I681- If' desired, the-end of the conduit I66 may be connecte'dwith the impact-tube 20 opening to-- ward the air stream and-adapted to receive the impactofairfiowing tli'roughtlie induction pas-- sage fromtlie-duct 26 so that said chamber 0' issubject'ed-toa pressure primarily derived from the source of air' or the duct byway of the impact tube I29.

Fuel-issupp'lied' to'the 'chamber I36 from a;

sourcepffuel-which is shown herein as a" tank" I 10, Figural, which may be'underground and/or remote from the heating unit, said fuel being taken from"the'tank'bya'pipe I12 connected with a-pump I14; driventlirougli a shaft I15 from the motor 28; and whicli'is'adapte'd to deliver fuel' to the pressurer'e'gulator I30, by means ofthe' pipe I16; at a substantially constant pressure; The" pipe I16 isconnected with a fuel inlet port in'the regulator. unit I30'which is controlled bya valve I18 and which has" a pin-like proj action. lfitl'int'o the'chamber' I36 in a, position'to' beenga'ge'd'byth'e head of rivet I56 whereby upward movement'of the diaphragxfi's', as viewed in' the drawings, opens the valve I18; 21 lights'p'fing I81 being providedto urge the valve I 18 toward its closed position. A spring I 84is mounted in chamber I48 on a boss I86 and its free end is received in a spring retainer portion of a pivoted lever I88 having a crimped central portion normally engaging the head of rivet I54 and urging the diaphragm upwardly in a direction to open the valve I18. If desired, the fuel supply to the piston may be cut off by closing valve I18 and, as shown, this may be effected by a plunger I98 which upon inward movement thereof engages the free end of lever I88 and moves the lever downwardly against the force of spring I84. The lever is thus moved out of engagement with rivet I54 whereby the light spring I82 may close the valve I 18 and thereby stop the flow of fuel to the carburetor. A spring urged ball I92 may be provided for engagement with an annular groove I94 in the plunger I 98 for releasably retaining said plunger in its inward position and if desired the plunger may be remotely controlled by any suitable mechanism; A pipe I9'6 having restricted communication with the top of the fuel chamber I36 may be provided for leading back to the fuel supply tank I18, vapors which may accumulate in the chamber I36. I

The discharge control unit I34 which regulates the metered fuel pressure, comprises a pair of easing members 288 and 282 between which is clamped a preformed annularly grooved flexible diaphragm 284 dividing the interior of the unit to chambers 286 and 288, chamber 286 being connected with chamber I36 of the regulator unit I38 by means of a conduit 2 I8 in which the metering orifice or jet I32 is located, and chamber 288 is connected with the Venturi annulus I84 by the passage I62. The diaphragm 284 is connected to a fuel outlet valve 2I2 urged downwardly, in a direction to close said valve, by a spring 2I4 arranged to be variably loaded by an adjustment screw 2I6, the stem of valve 2I2 being preferably of triangular cross-section or otherwise relieved to permit fuel flow therepast and is slidably disposed within a guide 2I8. The outlet of the discharge control unit is connected with thefuel pipe II2 leading to the fuel nozzle in the induction passage, and if desired, the pipe may include a portion adjacent the heater unit about which is disposed an electrical heating coil 228, one end of which may be grounded at 222 and the other end connected to a source of power or battery 32 by a wire 224. If desired, a thermostatic switch 226 may be interposed in the wire 224 and also a manually operated switch 228 may be interposed in said wire.

Operation of heating unit Assuming the carburetor has not been filled with fuel and the plunger I98 is in its outer position as shown, the spring I84 will urge the diaphragms upwardly and open valve I 18. Fuel under the pressure of pump I14, is delivered through pipe I 16, and enters and fills chamber I36 from which it flows through the metering orifice I32 and pipe 2I8 to the'chamber 286 of the discharge control unit I34, thence to the fuel nozzle in the induction passage by way of conduit II2. As the pressure in chamber I36 increases it acts against diaphragm I42 and tends to compress spring I84 whereby the valve I 18 tends to close while fuel under pressure supplied to chamber 286 acts on diaphragm 284 and tends to open valve 2 I 2. The screw 2 I6 is normally adjusted to compress spring 2 I 4 to such a point that a slightly lower pressure is required in chamber 286 to open valve 2I2 than is required in chamber I36 for sufficiently compressing spring I84 to permit valve I18 to close. Once the carburetor has been filled with fueLfuel will thereafter slowly spill from the nozzle unless plunger I98 is moved inwardly to compress spring I84 and allow valve I18 to close. described as being adjusted to permit valve 2I2 to open at a, pressure somewhat less than the closing pressure of valve I18, it will be apparent that by screwing the adjustment screw 2I6 in or out, the pressure in chamber 286 required to open valve 2I2 may, if desired, be made greater than, equal to or less than the pressure required in chamber I36 to permit valve I18 to close. It will also be apparent that the actual value or degree of the fuel pressures will be determined by the strength of springs I84 and 2 I4, the pressures required being greater as the strength of the spring is increased, and conversely the pressures required will be less as the strength of the springs is decreased.

During operation, the air flow through the Venturi I82 creates a differential between the impact pressure in the impact tube I28 and the pressure in the Venturi chamber I84/which varies as a function of the rate of air flow through the induction passage varies. The pressures in the Venturi chamber 584 and in the impact tube I28 are respectively transmitted to the chambers I38 and 288, and chamber I48, and control the opening of the valves I18 and 2I2 so as to regulate the flow of fuel to maintain a differential between unmetered and metered fuel "pressure which is in fixed proportion to Venturi to impact differential air pressure. The diaphragms I42 and I44 are shown as of unequal size, and assuming that the area ratio thereof is equal to 2, the regulator unit I38 functions to maintain a differential fuel pressure across the metering jet I32 which is equal to twice the differential air pressure. pressure at the Venturi chamber E84 is transmitted to chamber I38, where it results in an equal increment increase in the unmetered fuel pressure in chamber I36, and is also transmitted to chamber 288, where it results in an equal increment decrease in the metered fuel pressure.'

Consequently, the fuel metering differential pressure is increased an amountdouble the increase in the air difierential. Similarly, a given increase in the pressure of the air entering the Venturi is transmitted from the impact tube I28 tochamber I48 and since it is applied to the diaphragm I44 having twice the area of, diafl phragm I32, the unmetered fuel pressure in chamber I35 is increased an increment double theincrease in entering air pressure.

Although the diaphragms I42 and Hill are shown as having a 21 area relationship, they may be of anyother desired area ratio in which case the fuel metering differential pressure will be maintained at some multiple, other than 2, of the air pressure differential. For example, if the area of diaphragm 544 is three times the area of diaphragms I42, the fuel diiferential will be maintained equal to three times the air metering differential. In any case, however, the fuel and air differential pressures are maintained in constant proportions and therefore constant fuel to air proportioning is obtained.

From the foregoing it will be apparent that the control of unmetered and metered fuel onthe upstream and downstream sides respectively;

of the metering orifice I32 are separately con- Although the screw 2I6 has been For example, a given decrease in the trolled) therva'lm I18 controllfngsorrlyvthe pres sure off the unmeteredi fuel and-'1 thee 2:42? controlling the pressureoniyroffthemeteredzfuet.. Thea fuell discharged: rum-11 the ma groove Iii 5v ofithae -:firelznmizle isemixecliwith :the .air; from: theuaamnlet .Bltzofithe:in'ductiompassage aard'xthee mixture; thussformed enters: the: burneittuhe 5&3, passing; through: saidi tube-L. When. the: tuh'eai's: codd assdnrin'g thei'stamtingi'periodz thesfnet-i turn? is"? dischamged: from: the" orifices; a intbal a: combustion: chamber 64 anch tube: 6dr Ignition: 0i thesfiuel'mixturexisrefiected thecsparki plug: 12;. and: after: the: device has? been inzoperation an short: time the: burner? tube: 65,- together with:

the: metah shavings of'. steel; wool! 69) becomes;

heated. suiiicientl'io seas;- to more complete-15a va norize: the: mixtures thereim. said vaporized: fuel .mixturerbeingg discharged .irrtirltha' COIIlbElSE" tiomcham-ber M's Itais-to; be notedzthatr therend:

oi; tube: adj acents the fuel nozzle. is. disposed close: to said; nozzle: anoh in: linewith thee dis+- charge groove H6 of said nozzle so thaittlihetf-filf mixture will' enter theburner tube fifiwior vaporization: of said fmixture" by the: heated? steel :wool' and; burner tube:

The: thermostat 9& isadaptedi to control: the: throttle valve 922m such .amanner that as the: temperatureofthe thermostat drops the-throh tle valve *is opened thereby-supplyingithe burner. with alarger volume of.fuel-mixturetoincreasethe heat thereof and increasethe-- temperature of z the. air: passing through: the: beaten.

Operation of complete installation In. the preierred embodiment of the installer-,- tion, suchas -shownin Figured; the. electric ci-n cult for. the motor 28 includes the. thermostat disposed intlie room [2: and the-thermostat 42,: preferably disposedin the basement room-l Brad? jacentthe heatingunit. The thermostat 38 so constructed. and arranged that .l the. switch; thereof is. openedupon an. increase. in temperature. The-thermostat. 33. is adapted to control, the motor circuit for maintaining. the tempera! ture normally... desired in. a room, whereas thethermostat 42 is normallyadjusted to controlthe. circuit. at much. lower temperatures and to open upon -a.decrease in temperature. Thus-the. thermostat 38 primarily; controls 1 the roomtemperature. and. thethermostat- His: provided to out outthe. motor. only in; casestheburnen fails: to: function and the temperature adjacentttheretodrops a. substantial degree. As. hereinabovc: pointed out the thermostat.v 98. may belocatedl in theroom l2, if desired and. thuswontroltha opening and closing ofthe. throttle valvein accordance with room temperature. It is.to.be understood, of course, thatany otthethermznstats may be otherwise located than asshown in the drawings, the locations depending uponthe installation and type. of. control desired.

When the system is being'used the switch. 511i ofthe bypass 48-is opened; However, should'it be desired torender the thermostat Minoperative to control the motor circuit, the switchifl is closed. and the motor circuit is then controlledentirely, bythe thermostat 38. This arrangementmay be desirable under some circumstances" when" the system is functioning to heat the building; although the arrangement may also be. useful. should the air circulating system be connected. with an air conditioning unit whichis not shown but which may be of any commercial type, for. circulating cooled. air throughout the. buildingv when theweather'ls hot. The bypass arrange.-

8; menb'. 508 mayvalsosb'e useiul: ir'nstartings tires heating :apparatus: when the: temperaturenisasui fibiently; low. to eflect: opening: ot. the switch oil thBrmOSliMtl. Thesswitch ifll-cisnthenzclosed. so:

. that .thesystem liSiCDIIbI'UH'e (tiny thermostat." the switch: or: whichds closed: at: such.1oWtempera-- tures Thusstha-electrical contr0l-:chm1itis::oper-- able until: thee temperature :iIIJ the room: reaches; thesdesiredzvaluez'. After the-..-temnerature of the heating; unit: becomes: sufiiciently' warm for: the? switch; of thermostat 42- to.- close; the. switch. 58% mayrberopenedl- Thereiorethathermostat- 42 pro? vides-asafety factor .for shuttinEtofi-the-apparatus: inlcasestheibnrnerl fails-torfunotion and the-tent mature adjacent thereto; dropst a substantial;

amounts 7 Anzairt conditioning:system. may, .if: desired, be; connected to.- the air: circulating system of; the present-invention by: means; of. a-.conduit A de-. live-ringv conditioned air 'to :conduit-l 4=-through an;- opening, 301; said lopeningubeing-r normally closed.- by arvalveelike. door 302. when' the. air conditioningnnit ,isenotrconnectedrwith said air circulatings system.

Althoughlbuttone modification of-the invention has been particularly shown and desmibedrit-Js. believedthatdtwi-ll 'bel-obviousthatmanyl changes maybe. madeimthe form, constructionland are rangementofltheparts anditlisnotintended that. thescopevof.theinvention-should belimited to the. embodiment shownsand. described nor otherwise. excepthy the. termsottheappended claims.-

we claim; 7

1*. In a.- heating 7 system; for: buildings and: the like: .aheater comprising1 a-.casing a-.carburetingz deviceadisposed: within the: casingtand v having ant induction. passage therein; an air" duct for comveyingl-heatedlairatoetheiroom .tosbeheated; elect-.- trically operated:meansfor inducingra .flow'ofiain through the casing, andthef inductiom passages: a source of; electric power for: the last mentioned: means; atemperature. responsive-device adapted: tonbe disposedhinrasroomlto be-heatedr; a. seconct temneratureerespitnsivexieviceadjacent:the/heati-- er. and 1 adapted to'cut oh: the source? or electric; powen to. the electrically operatedlmeansnporr-aa decrease; irn temperature?- below. a. predeterminedi value; said. temperature:responsivedevices: being: connectedinsseriesg .theefirst mentionedttempera turn. responsive:- device beingrlocated'iin an upper. portion of a-room to :be heated; anthird tempera-- tureresponsivesdevice adapted: to. bee di'sposed'ad jacenttthe-fioor. of; said; room; a valVe-zcontrolling' the. fluid fiow throughz the; induction passage of the charge forming devicei'andlaa linkage *between the third mentioned. temperatureresponsive device and the valvewhereby the latter is temperatureicontrolleda 2:In a heating system fbr'buildings' and the. like: aiheater comprisinga-casihg; acarbureting device disposed Withiir the casing and havingtan' induction passage disposed therein; a duct for conveying heatediair: to a -room-tobe heated; elc= trica-llyv-operateditmeans for inducing-'2: fibwof air triccircuittfnnthelast mentioned' means a tennperature responsivedevice adapted to' be disposed in: theeroomzto: he heated; a: second temperature responsive; devicei adjacent theheater; said ternnerature: responsive: devices being: connected in serieseandradaptcd tucontrofisaifielectric circuit? a balanced throttle controlling. the flowof fuel tln'oughthednductiom passage; and: a1 temperatureeresponsive, device :linhemwithzthewthrottle nfon controlling-,thenositionzthereoiz 3. In a heating system for buildings and the like: a heater comprising a casing; a. carbureting device disposed within the casing having an induction passage therein; a throttle valve in said induction passage; electrically operated means for inducing a flow of air through said casing and the induction passage; an electric circuit for the last mentioned means; a temperature responsive device disposed in the room to be heated and adapted to open upon an increase in temperature; a second temperature responsive device adjacent the heater and adapted to open upon a decrease in temperature; said temperature responsive devices oeing connected in series in the electric circuit; and a third temperature responsive device disposed in the room to be heated and linked with the throttle valve of the induction passage for controlling same.

4. The invention defined by claim 3 wherein the third mentioned temperature responsive device is adapted to move the valve in the opening direction upon a decrease in temperature.

EMIL O. WIRTH. FREDERIK BARFOD.

REFERENCES CITED The following references are of record in the file of this patent: 

